Such deck-chairs usually comprise rack-type toothings provided in or applied to both sides of the seat or back--however on opposite sides of the chair--and locking pins interacting with said toothings in order to establish the different positions of use of the deck-chair.
The known structures however are not free from disadvantages, which usually occur when choosing or changing position of use of the deck-chair. In fact, it may happen that the locking pins do not coincide with, and do not correctly pass through, the corresponding grooves, or that the locking pins have difficulties in positioning in the toothing when the parts of the deck-chair are reciprocally displaced for the desired position, or when a deck-chair is moved to another place.